12 Yongqi Gao 23 Noel Keenlyside 12 Torben Koenigk 4 Vladimir Semenov 5 Lingling Suo 23 Shuting Yang 6 Tao Wang 7 1 Geophysical Institute University of Bergen Norway ID: 604691
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Slide1
Fumiaki Ogawa
1,2
, Yongqi Gao2,3, Noel Keenlyside1,2, Torben Koenigk4, Vladimir Semenov5, Lingling Suo2,3, Shuting Yang6, Tao Wang71Geophysical Institute, University of Bergen, Norway. 2Bjerknes Centre for Climate Research, Norway. 3Nansen Environmental and Remote Sensing research Center, Norway. 4Swedish Meteorological and Hydrological Institute, Sweden. 5Helmholtz Centre for Ocean Research Kiel, Germany. 6Danish Meteorological Institute, Denmark. 7Chinese Academy of Sciences, Institute of Atmospheric Physics, China.
Impact of SIC/SST for multi-decadal climatic trends;
Results from coordinated AGCM experimentsSlide2
EXP1 – daily SIC & SST as observed
NOAA daily data (1982-2013)
Six AGCMs20 member ensembles for each modelEXP2 – SIC is same but SST is daily climatology Slide3
Simulated 2m Temperature
trend [K/10yr
]SONEXP1(MME)1982-2013EXP2 (MME)1982-2013DJFERA-
Int
1982-2013
Shaded for
95% confidence.
Consistent among AGCMs
ATL
PAC
EURASIA
G
-Warming is local & similar (
W
W
W
W
W
W
d
isagrees among reanalysis
[
Lindsay et al. 2015]
)
Similar
-Polar warming pattern is due to SIC (EXP1–EXP2=SST impact)Slide4
DJF
EXP1(MME)
1982-2013EXP2 (MME)1982-2013ERA-Int1982-2013On the wintertime warming in GREENLAND (T2m)
•GREENLAND warming is
due to
SIC.
•Tropical variability of SST (Ding et al. 2014) is not required.Slide5
DJF
•Warming in north-east U.S. is simulated as observed: SIC impact
EXP1(MME)1982-2013EXP2 (MME)1982-2013ERA-Int1982-2013
On the wintertime warming in north-east U.S (T2m)Slide6
On the wintertime cooling trend in Siberia (T2m)
•Siberian cooling is not simulated in EXP1/2
EXP1(MME)1982-2013EXP2 (MME)1982-2013ERA-Int
1982-2013Slide7
DJF
• Observed Siberian cooling is nothing to do with SST/SIC change.
DJFSLP
Absence of SLP trend;
s
iberian
cooling disappears.
(
McCusker
et al. 2016
)
EXP1(MME)
1982-2013
EXP2 (MME)
1982-2013
ERA-
Int
1982-2013
On the wintertime cooling trend in Siberia (T2m)Slide8
EXP1(MME)
1982-2013
EXP2 (MME)1982-2013DJFT2mERA-Int1982-2013DJFLHF
Correspondence to upward LHF
trends
[W/m2/
10yr
]
BK
BK
BK
•SIC impacts B-K
and north-eastern U.S.
warmings
through LHF.
•Note: GREENLAND warming is not due to LHF.Slide9
EXP1(MME)
1982-2013
EXP2 (MME)1982-2013DJFT2mERA-Int1982-2013DJFLR
Trend of upward net long-wave radiation at the surface
BK
BK
BK
Main cause of unrealistic
c
ooling is mainly by jump of NOAA-SIC in the region (2005)
•SIC impacts warming in B-K regions also through LR.Slide10
JF
SO
NDObserved surface warming in JF is local: N-E.U.S., B.K., GREENLAND: reproduced in EXP1/2. AA is less clear above even in reanalysis. Model shows little contribution of SST/SIC.
ERA-I warming lat.
almost coincides to EXP1/2.
Zonal mean Temperature trends
“Arctic amplification (AA)”
EXP1(MME)
1982-2013
EXP2 (MME)
1982-2013
ERA-
Int
1982-2013
•Simulated warming is centered in SIC changing latitudes.
SIC impact is limited in
l
ower troposphere
(Screen et al. 2012)Slide11
Summary: Impact of SIC/SIC for the observed trends
Autumn and early winter:
•AA is influenced by SIC, but limited near the surface. Arctic Amplification:Impact of SST is dominant above. (supporting Screen et al. 2012) •Seems like internal variablity of atmosphere, nothing to do with SST/SIC. •SIC seems relevant for spatial distribution of land surface temperature trend.
Late winter: AA itself become less obvious.
-Surface AA is rather localized: still explained by SIC impact
-Warming above is not clear: little contribution by SST/SIC
Thermodynamics for the warming trends is need to be addressed more in detail...
Siberian cooling in winter:
- supporting (
McCusker
et al. 2016)
: Tropical SST change (Ding et al. 2014) seems not required.
GREENICE COORDINATED experiments have made implications for previous findings: